Can anybody tell me what current/modern flash unit is rated at 100 ws? or is there a (rough) conversion from Watt seconds to lumen seconds, to Guide numbers?

You can get some small studio strobes at 100ws. The way it was explained to me you can't simply convert. 100ws is a measure of the amount of power going in. GN is a measure of the light going out. The reflector matters. How good the strobe is with using power.

Yeah I knew the efficiency of the electronics, polished reflector, even the size and color of the room effect the GN, I was just looking for a 'ball park figure" and you gave me one.

And it's what I feared

So I would have a flash that weighs 5 pounds with a pack that would weigh at the very least 8 pounds and produce a guide number equal to or less than a 283 Vivitar with 4 penlights which has a guide number of 120.

On 2004-07-09 18:36, Les wrote:
Yeah I knew the efficiency of the electronics, polished reflector, even the size and color of the room effect the GN, I was just looking for a 'ball park figure" and you gave me one.

And it's what I feared

So I would have a flash that weighs 5 pounds with a pack that would weigh at the very least 8 pounds and produce a guide number equal to or less than a 283 Vivitar with 4 penlights which has a guide number of 120.

But I'd look real cool doing it!

[ This Message was edited by: Les on 2004-07-09 18:36 ]

Um, Les, I have two 283s, also a Minolta Flash Meter. Yes, the original one. The meter says the 283s' full power GNs are 80 and 90. You should know better than to believe most manufacturers' published GNs.